%I A124231
%S A124231 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,
%T A124231 27,28,31,32,33,34,35,36,79,80,81,82,137,138,193,194,195,196,257,258,
%U A124231 259,260,261,262
%N A124231 Numbers n such that pi(n) is palindromic, where pi(n) is the number of 
               primes less than or equal to n.
%e A124231 Every number from 1 to 28 inclusive belongs to this sequence as the number 
               of primes less than or equal k, which is not more than 28 is a one 
               digit number, which is a palindrome.
%t A124231 Select[Range[300], Reverse[IntegerDigits[PrimePi[ # ]]] == IntegerDigits[PrimePi[ 
               # ]] &]
%Y A124231 Sequence in context: A160546 A087143 A080683 this_sequence A154470 A090106 
               A167662
%Y A124231 Adjacent sequences: A124228 A124229 A124230 this_sequence A124232 A124233 
               A124234
%K A124231 base,nonn
%O A124231 1,2
%A A124231 Tanya Khovanova (tanyakh(AT)yahoo.com), Dec 13 2006